Background <p>Excessive accumulation of body fat, particularly abdominal and visceral fat, is a major risk factor for metabolic abnormalities and chronic diseases. This study evaluated the safety and effects of 12-week HFN2-008 supplementation on body fat distribution and abdominal fat in adults.</p> Methods <p>A 12-week randomized, double-blind, placebo-controlled exploratory pilot study was conducted in 100 adult men and women. Participants were randomly assigned to receive either HFN2-008, a formulation containing heat-treated <i>Bifidobacterium longum</i> HN001 dried culture powder, or a placebo. Body fat mass and percentage were assessed using dual-energy X-ray absorptiometry, whereas abdominal fat areas were assessed using computed tomography.</p> Results <p>After 12 weeks of supplementation, the HFN2-008 group demonstrated significantly greater decreases in trunk and total body fat mass and percentage compared with the placebo group. Computed tomography further revealed significant decreases in visceral and subcutaneous fat areas in the HFN2-008 group compared with the placebo group. No significant between-group differences were observed in lean body mass or circulating metabolic biomarkers. No serious adverse events were reported, indicating a favorable safety profile.</p> Conclusions <p>HFN2-008 effectively decreases body and abdominal fat without loss of lean body mass and appears to be a safe functional ingredient for body fat management in adults.</p> Trial registration <p>Registry: Clinical Research Information Service, TRN: KCT0011178, Registration date: 19 November 2025</p>